Urethane-(meth)acrylic composite resins are used as cosmetics for retaining hair style, protecting skin or the like, utilizing the film-forming ability thereof (see, the below-identified Patent Documents 1 and 2), or alternatively, as coatings for industrial (for automobiles) or household use, or protective films (see, the below-identified Patent Document 3). However, when a film made of such a resin comes into contact with an oily component, there are cases where the film is dissolved or swollen due to insufficient oil resistance, failing to fully exhibit its performance.
Although an approach such as using a resin having a higher molecular weight or increasing the content of hard segment may be used in order to improve the oil resistance, there are cases where the resulting film may be too hard, thereby reducing the conformability to a base material, and resulting in a peeling when the film is bent, or causing stiffness or discomfort upon use when used as a cosmetic.
As synthetic resins to be used in cosmetics, polymers such as acrylic resins, vinyl acetate resins, vinyl pyrrolidone resins, and vinyl methyl ether resins, of varying ionicity such as anionic, cationic, nonionic or amphoteric ionicity, are widely known. These synthetic resins are used for the purpose of retaining hair style or protecting skin, utilizing their film-forming ability. However, a problem has been pointed out that the resulting film may be too hard or sticky, depending on the resin used.
As a resin for use in a cosmetic in which drawbacks pointed out in the above mentioned resins, such as stiffness or hygroscopicity, are improved, an aqueous dispersion is proposed which contains a urethane-acrylic composite resin composed of composite particles obtained by copolymerization of radical polymerizable monomers in the presence of polymer particles of polyurethane (see the below-identified Patent Documents 1 and 2).
An example of the cosmetics including the resin for use in a cosmetic as described above is a “hair styling agent”, which is a hair cosmetic, and it can be prepared in a variety of forms, including an aqueous formulation for use as a mist spray, and a hair wax containing a large amount of an oily component. The resins for use in cosmetics have been widely used not only in hair cosmetics, but also in make-up cosmetic applications, sun care cosmetic applications (such as sunscreens), and skin care cosmetic applications (for protecting skin and providing moisture), for example.